I was reading over at the shephard’s Scrapbook about legalism. I agree that legalism is a huge soteriological issue. We fall into it without noticing it. When ever we think God is more please with us because of our obedience than any other of his children we have fallen to this sinful trap. Tony Reinke states the well:
Legalism is the lie that God will find more pleasure in me because my obedience is greater than others or that God looks at me with disgust because I am not growing in grace as quickly as my friends. It is the failure to remember that God’s pleasure in us comes outside of us (in Christ). Legalism causes the heart to forget that God sings over us because of the work He has done, not because of what we have done (Zeph. 3:15-17).
Believers equally bring pleasure to God because the pleasure He receives in us is the purchased pleasure of the substitution of Jesus Christ. Any imagined superiority to other Christians (not rules or a lack of rules) is the sure sign of the legalist.
You can read the rest of his post: Understanding Legalism